[Bug] Local time signature change breaks double barline

Bug report:

In the attached screen shot, I added double barlines at bars 5 and 9. In the oboe staff at bar 5, I added a local time signature change. This caused the double barline at bar 9 to become a single barline on all staves except the oboe staff, and the barline connections above and below the oboe staff disappeared. (Fortunately this can be repaired by re-selecting the barline at bar 9 and changing it back to a double barline.)

This is an expected limitation. Every special barline (double/repeat etc.) contains a time signature, though by default that time signature is hidden. If you add an independent time signature, you’re replacing that special barline.

Even so, it’s weird that it changes the barlines on all of the other staves, rather than the one with the independent time signature, and it breaks the barline connections above and below the staff with the independent time signature which seemingly has nothing to do with the type of barline. Seems like it should be possible for Dorico to avoid doing these things. Of course, adding the independent time sig first, and then adding the double bars, will avoid the situation, but it would be nice for the other sequence of steps to work as well.

For your situation there is an opposite situation where someone expects it to be the oboe that retains the double barline, and the other instruments to get a single barline. Whatever Dorico does here, someone’s going to complain.

Thankfully you now know how Dorico handles these things, and which order to perform these steps in.

After some more experimentation, I’ve discovered that adding the independent time signature first and then changing the barline to a double barline does not work. When you change the barline type after adding the independent time signatures, only the staves without an independent time signature get a double bar; the staves with an independent time signature stay as single barlines. So you must change the barline type first, and then add the independent time signatures.

Adding independent time signatures messes up downstream double barlines, though, so you have to make sure that when you add the independent time signatures there are no double barlines downstream. You can add the downstream double barlines only after you’ve added the (upstream) independent time signatures. If you’re going to have more independent time signature changes further downstream, you must wait to add further downstream double barlines until after you’ve added the upstream independent time signatures, and you must change the barline type at the independent time signature bar before adding the time signature.

This still seems like a bug to me.

This isn’t quite true. Look:

When you introduce an independent time signature, Dorico automatically localises that barline, so you can do things like this:

It does mean that, having created a local time signature, you need to change the barline twice: once with the Alt key held and once without.

Aha! Thanks, Leo. I hadn’t thought about the possibility of changing the barline of just that one staff using alt-enter. Does that restore the barline connections above and below the affected staff as well? I’ll have to give that a try and see.

…And the answer is yes, it does restore the barline connections. I guess the reason the barline connections are removed in the first place is that Dorico won’t connect different barline types between staves. Once you’ve restored the double barline on the affected staves and they match the staves above and below, the barlines are connected per the bracketing setup.

So I guess this isn’t a bug, but perhaps there is some room for improvement in the implementation here.

Thanks again for your help, Leo. You’re a valuable resource here on the forum.

If you’ve a) got the layout option set for coincident polymetric barlines to join and b) the staves are generally bracketed together then yep, they should all join up nicely.

(I think it’s a layout option - I’m not in front of the computer this second.)

The option in question is on the Barlines page of Engraving Options (‘Coincident barlines in polymetric music’), and is set to ‘Break coincident barlines’ by default.

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